So, in Windows File Explorer you can assign a custom view to each separate folder, but in Directory Opus 12 Pro if you assign a custom view, let's say thumbnails, then every other folders will now have that custom view.
How can I assign a custom view to every single folder I need to without changing the overall default folders' view?
Open the Folder Options dialog and click Save. One of the options lets you save it for just that folder.
The first Folder Formats FAQ shows how to get to the Folder Options dialog if you can't find it.
You can also set up formats which apply to multiple paths using wildcards and other criteria, via Preferences / Folders / Folder Formats.
Actually when reading your article "Folder Formats: Quick Guide" I realized the option "Enable Folder Content Type detection" was really what I was looking for in the first place rather than setting each folder manually; so I just turned that on and relaunched Opus, but unfortunately it doesn't seem to work as folders with lots of image or wallpapers have retained the standard view
the other settings are almost all vanilla, what should I do?
Did you edit the Images content type format to tell it to use Thumbnails mode?
It can do that if you tell it to, but only adds some extra columns by default.
You can edit it in Preferences / Folders / Folder Formats.
Alright thanks, I figured it out